/*
 * This file Copyright (c) 2015. Walle.
 * (http://www.wallellen.com). All rights reserved.
 *
 *
 * This file is dual-licensed under both the
 * Walle Agreement (WA) and the GNU General Public License.
 * You may elect to use one or the other of these licenses.
 *
 * This file is distributed in the hope that it will be
 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
 * Redistribution, except as permitted by whichever of the GPL
 * or WA you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or
 * modify this file under the terms of the GNU General
 * Public License, Version 3, as published by the Free Software
 * Foundation.  You should have received a copy of the GNU
 * General Public License, Version 3 along with this program;
 * if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 2. For the Walle Agreement (WA), this file
 * and the accompanying materials are made available under the
 * terms of the WA which accompanies this distribution, and
 * is available at http://www.wallellen.com/agreement.html
 *
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 */

/**
 *
 */
package com.wallellen.wechat.common;

import org.apache.commons.codec.digest.DigestUtils;

import java.util.Arrays;

/**
 * 用于微信的前面验证
 *
 * @author <a href="mailto:wallellen@hotmail.com">WALLE</a>
 * @date 2014-12-4
 */
public class ValidateSignature {

    private String signature;
    private String timestamp;
    private String nonce;
    private String token;

    /**
     * 前面验证构造
     *
     * @param signature
     * @param timestamp
     * @param nonce
     * @param token
     */
    public ValidateSignature(String signature, String timestamp, String nonce, String token) {
        this.signature = signature;
        this.timestamp = timestamp;
        this.nonce = nonce;
        this.token = token;
    }

    /**
     * 验证
     *
     * @param token
     * @return true 验证通过，false 验证失败
     */
    public boolean check() {
        String sha1 = encode();
        return sha1.equals(this.signature);
    }

    /**
     * 得到加密后的数据
     *
     * @return
     */
    private String encode() {
        String[] sa = {this.token, this.timestamp, this.nonce};
        Arrays.sort(sa);
        String sortStr = sa[0] + sa[1] + sa[2];
        return DigestUtils.sha1Hex(sortStr);
    }
}
